function re() {
    let na = document.getElementById("name").value;
    console.log(na);
    let ss = document.getElementById("pass").value;
    if (na === '') {
        alert('用户名不能为空，请重新填写');
        return;
    }
    else if (ss.length < 6) {
        alert('密码长度不能低于6位');
        return;
    }
    alert('注册成功');
}